Bug 775363 - Bump minimum CMake version to 3.1
Bug 775363 - Bump minimum CMake version to 3.1

That's to keep in sync with the evolution-data-server and evolution,
where the bump was done due to usage of 'cmake -E env', which had
been added in the CMake 3.1.

GNOME/evolution-ews,GNOME/evolution-ews